Anastomosis is the surgical joining of separate hollow organ sections to allow the sections to communicate with each other. An anastomosis can follow a procedure in which a section of hollow tissue is removed, such as a section of the intestine, and the remaining end sections are to be joined. Depending on the desired anastomosis procedure, the end sections may be joined end-to-end or side-to-side, for example.
Circular surgical stapler instruments that perform an anastomosis procedure are known. The instrument joins two ends of the organ sections by driving a circular array of staples through the organ sections and cutting the tissue to form a tubular passage. The instrument includes an actuating handle assembly and a tubular body portion extending therefrom. The body portion receives a staple cartridge assembly and has a shaft that connects to an anvil assembly. Retraction of the shaft clamps tissue between the anvil assembly and the staple cartridge assembly. Staples are driven into staple receiving recesses and the tissue is cut by a circular knife. See U.S. Pat. No. 5,443,198 to Viola et al., the entire disclosure of which is hereby incorporated by reference herein.
After the staples have been fired, the entire instrument must be removed from the site. The anvil assembly has a rigid anvil head and has a profile that can make it difficult to remove the instrument from the tubular organ.
In order to reduce the transverse profile of the anvil assembly during placement and removal of the anvil assembly from a hollow organ, anvil assemblies having a tiltable anvil head have been developed. One such anvil assembly is described in U.S. Pat. No. 6,053,390, filed on May 10, 1999, which is hereby incorporated by reference herein, in its entirety. The pivotable anvil head is normally locked in the operative firing position. Upon firing the stapling device, the lock is released and the anvil head moves to a position that is tilted with respect to the shaft.
A need still exists for an improved surgical stapling instrument having an anvil assembly that minimizes the difficulties associated with removing the instrument after it has been fired, and that is easier to deliver into hollow tissues to be joined.